Control and drive of a rotating machine with an inner and an outer stator

Abstract

A method for continuous operation of a rotating machine, the method is performed in a rotating machine having an inner stator and an outer stator. The method includes setting a rotating machine reference operational value for the whole rotating machine, obtaining operational parameters for the inner stator and for the outer stator, wherein the operational parameters include magnetic cross-coupling between the inner and outer stators, determining an inner stator reference operational value for the inner stator and an outer stator reference operational value for the outer stator based on the set rotating machine reference operational value for the whole rotating machine and the obtained operational parameters, and driving the rotating machine based on the determined inner stator reference operational value for the inner stator and on the determined outer stator reference operational value for the outer stator, wherein the determined inner stator reference operational value for the inner stator differs from the determined outer stator reference operational value for the outer stator.

The invention claimed is: 
     
       1. A method for continuous operation of a rotating machine, the method being performed in a rotating machine having an inner stator and an outer stator, comprising:
 setting a rotating machine reference operational value for the whole rotating machine; 
 obtaining operational parameters for the inner stator and for the outer stator, wherein the operational parameters include magnetic cross-coupling between the inner and outer stators; 
 determining an inner stator reference operational value for the inner stator and an outer stator reference operational value for the outer stator based on the set rotating machine reference operational value for the whole rotating machine and the obtained operational parameters; and 
 driving the rotating machine based on the determined inner stator reference operational value for the inner stator and on the determined outer stator reference operational value for the outer stator, wherein the determined inner stator reference operational value for the inner stator differs from the determined outer stator reference operational value for the outer stator. 
 
     
     
       2. The method according to  claim 1 , wherein the inner stator is driven by a power unit independently from a power unit for the outer stator. 
     
     
       3. The method according to  claim 1 , wherein the rotating machine, inner stator and outer stator reference operational values are for one of the following: power, torque and speed. 
     
     
       4. The method according to  claim 1 , wherein the operational parameters for the inner and outer stators further includes one or more of the following: rotation position, inductance, flux linkage, magnetic coupling, current component, current position, resistance, loss variation and temperature dependence. 
     
     
       5. The method according to  claim 1 , wherein the operational parameters are obtained by measurements and/or table look-up. 
     
     
       6. The method according to  claim 1 , wherein the inner stator reference operational value for the inner stator comprises individually set values for direct current and for quadrature current, and the outer stator reference operational value for the outer stator includes individually set values for direct current and quadrature current. 
     
     
       7. A control and drive system for a rotating machine having an inner stator and an outer stator, the control and drive system comprising:
 a controller device for a rotating machine, configured to set a rotating machine reference operational value for the whole rotating machine, to obtain operational parameters for an inner stator and for an outer stator of the rotating machine, wherein the operational parameters includes cross-coupling between the inner and outer stators, and to determine an inner stator reference operational value for the inner stator and an outer stator reference operational value for the outer stator based on the set rotating machine reference operational value for the whole rotating machine and the obtained operational parameters; and 
 a power device arranged to drive the rotating machine based on the determined inner stator reference operational value for the inner stator and on the determined outer stator reference operational value for the outer stator, wherein the determined inner stator reference operational value for the inner stator differs from the determined outer stator reference operational value for the outer stator. 
 
     
     
       8. The control and drive system according to  claim 7 , wherein the power device comprises a first power unit for the inner stator and a separate second power unit for the outer stator, wherein the inner stator is driven independently from the outer stator. 
     
     
       9. The control and drive system according to  claim 7 , wherein the controller device comprises a first control unit for the inner stator and a separate second control unit for the outer stator, wherein the inner stator is driven separately from the outer stator. 
     
     
       10. The control and drive system according to  claim 7 , wherein the rotating machine, inner stator and outer stator reference operational values are for one of the following: power, torque and speed. 
     
     
       11. The control and drive system according to  claim 7 , wherein the operational parameters for the inner and outer stators further includes one or more of the following: rotation position, inductance, flux linkage, magnetic coupling, current component, current position, resistance, loss variation and temperature dependence. 
     
     
       12. The control and drive system according to  claim 7 , wherein the operational parameters are obtained by measurements and/or table look up. 
     
     
       13. The control and drive system according to  claim 7 , wherein the inner stator reference operational value for the inner stator comprises individually set values for direct current and for quadrature current, and the outer stator reference operational value for the outer stator includes individually set values for direct current and quadrature current. 
     
     
       14. A computer program for continuous operation of a rotating machine having an inner stator and an outer stator, the computer program comprising computer program code which, when run on a controller, causes the controller to:
 set a rotating machine reference operational value for a whole rotating machine; 
 obtain operational parameters for an inner stator and for an outer stator of the rotating machine, wherein the operational parameters include cross-coupling between the inner and outer stators; 
 determine an inner stator reference operational value for the inner stator and an outer stator reference operational value for the outer stator based on the set rotating machine reference operational value for the whole rotating machine and the obtained operational parameters; and 
 drive the rotating machine based on the determined inner stator reference operational value for the inner stator and on the determined outer stator reference operational value for the outer stator, wherein the determined inner stator reference operational value for the inner stator differs from the determined outer stator reference operational value for the outer stator. 
 
     
     
       15. A computer program product comprising a computer program which generates controller signals to:
 set a rotating machine reference operational value for a whole rotating machine; 
 obtain operational parameters for an inner stator and for an outer stator of the rotating machine, wherein the operational parameters include cross-coupling between the inner and outer stators; 
 determine an inner stator reference operational value for the inner stator and an outer stator reference operational value for the outer stator based on the set rotating machine reference operational value for the whole rotating machine and the obtained operational parameters; and 
 drive the rotating machine based on the determined inner stator reference operational value for the inner stator and on the determined outer stator reference operational value for the outer stator, wherein the determined inner stator reference operational value for the inner stator differs from the determined outer stator reference operational value for the outer stator.